/**
*
*  SHA256 (Secure Hash Algorithm) for use in pidCrypt Library
*  Depends on pidCrypt (pidcrypt.js, pidcrypt_util.js)
*
*  For original source see http://anmar.eu.org/projects/jssha2/
*  Download: 09.06.2009 from http://anmar.eu.org/projects/jssha2/
* 
**/
/* A JavaScript implementation of the Secure Hash Algorithm, SHA-256
 * Version 0.3 Copyright Angel Marin 2003-2004 - http://anmar.eu.org/
 * Distributed under the BSD License
 * Some bits taken from Paul Johnston's SHA-1 implementation
 */

if(typeof(pidCrypt) != 'undefined') {
  pidCrypt.SHA256 = function(s) {

/* A JavaScript implementation of the Secure Hash Algorithm, SHA-256
 * Version 0.3 Copyright Angel Marin 2003-2004 - http://anmar.eu.org/
 * Distributed under the BSD License
 * Some bits taken from Paul Johnston's SHA-1 implementation
 */
    var chrsz = 8;  /* bits per input character. 8 - ASCII; 16 - Unicode  */
    function safe_add (x, y) {
      var lsw = (x & 0xFFFF) + (y & 0xFFFF);
      var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
      return (msw << 16) | (lsw & 0xFFFF);
    }
    function S (X, n) {return ( X >>> n ) | (X << (32 - n));}
    function R (X, n) {return ( X >>> n );}
    function Ch(x, y, z) {return ((x & y) ^ ((~x) & z));}
    function Maj(x, y, z) {return ((x & y) ^ (x & z) ^ (y & z));}
    function Sigma0256(x) {return (S(x, 2) ^ S(x, 13) ^ S(x, 22));}
    function Sigma1256(x) {return (S(x, 6) ^ S(x, 11) ^ S(x, 25));}
    function Gamma0256(x) {return (S(x, 7) ^ S(x, 18) ^ R(x, 3));}
    function Gamma1256(x) {return (S(x, 17) ^ S(x, 19) ^ R(x, 10));}
    function core_sha256 (m, l) {
        var K = new Array(0x428A2F98,0x71374491,0xB5C0FBCF,0xE9B5DBA5,0x3956C25B,0x59F111F1,0x923F82A4,0xAB1C5ED5,0xD807AA98,0x12835B01,0x243185BE,0x550C7DC3,0x72BE5D74,0x80DEB1FE,0x9BDC06A7,0xC19BF174,0xE49B69C1,0xEFBE4786,0xFC19DC6,0x240CA1CC,0x2DE92C6F,0x4A7484AA,0x5CB0A9DC,0x76F988DA,0x983E5152,0xA831C66D,0xB00327C8,0xBF597FC7,0xC6E00BF3,0xD5A79147,0x6CA6351,0x14292967,0x27B70A85,0x2E1B2138,0x4D2C6DFC,0x53380D13,0x650A7354,0x766A0ABB,0x81C2C92E,0x92722C85,0xA2BFE8A1,0xA81A664B,0xC24B8B70,0xC76C51A3,0xD192E819,0xD6990624,0xF40E3585,0x106AA070,0x19A4C116,0x1E376C08,0x2748774C,0x34B0BCB5,0x391C0CB3,0x4ED8AA4A,0x5B9CCA4F,0x682E6FF3,0x748F82EE,0x78A5636F,0x84C87814,0x8CC70208,0x90BEFFFA,0xA4506CEB,0xBEF9A3F7,0xC67178F2);
        var HASH = new Array(0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19);
        var W = new Array(64);
        var a, b, c, d, e, f, g, h, i, j;
        var T1, T2;
        /* append padding */
        m[l >> 5] |= 0x80 << (24 - l % 32);
        m[((l + 64 >> 9) << 4) + 15] = l;
        for ( var i = 0; i<m.length; i+=16 ) {
            a = HASH[0]; b = HASH[1]; c = HASH[2]; d = HASH[3]; e = HASH[4]; f = HASH[5]; g = HASH[6]; h = HASH[7];
            for ( var j = 0; j<64; j++) {
                if (j < 16) W[j] = m[j + i];
                else W[j] = safe_add(safe_add(safe_add(Gamma1256(W[j - 2]), W[j - 7]), Gamma0256(W[j - 15])), W[j - 16]);
                T1 = safe_add(safe_add(safe_add(safe_add(h, Sigma1256(e)), Ch(e, f, g)), K[j]), W[j]);
                T2 = safe_add(Sigma0256(a), Maj(a, b, c));
                h = g; g = f; f = e; e = safe_add(d, T1); d = c; c = b; b = a; a = safe_add(T1, T2);
            }
            HASH[0] = safe_add(a, HASH[0]); HASH[1] = safe_add(b, HASH[1]); HASH[2] = safe_add(c, HASH[2]); HASH[3] = safe_add(d, HASH[3]); HASH[4] = safe_add(e, HASH[4]); HASH[5] = safe_add(f, HASH[5]); HASH[6] = safe_add(g, HASH[6]); HASH[7] = safe_add(h, HASH[7]);
        }
        return HASH;
    }
    function str2binb (str) {
      var bin = Array();
      var mask = (1 << chrsz) - 1;
      for(var i = 0; i < str.length * chrsz; i += chrsz)
        bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (24 - i%32);
      return bin;
    }
    function binb2hex (binarray) {
      var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */
      var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
      var str = "";
      for (var i = 0; i < binarray.length * 4; i++) {
        str += hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8+4)) & 0xF) + hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8  )) & 0xF);
      }
      return str;
    }
    function hex_sha256(s){return binb2hex(core_sha256(str2binb(s),s.length * chrsz));}
    //s = pidCryptUtil.encodeUTF8(s);
    return binb2hex(core_sha256(str2binb(s), s.length * chrsz));

  }
}